Considering how similar the main couples are in these two dramas. I'm surprised it's not even recommended. The genre is completely different. Memory Lost is a detective drama. The elite detective team vs. a team of criminal masterminds.

But I think Memory Lost amends the main weakness of Love O2O. The lack of chemistry. Xiao Nai is more often creepy than charismatic. Bei Wei Wei rarely shows any emotion other than blushing. While handling of plot, side characters etc. is awesome. A romance drama is incomplete if you can't feel the chemistry between the leads.

On the other hand while Han Chen is pretty possessive like Xiao Nai it comes off as more lovey dovey rather than creepy. Acting of Bai Xin Ji is leagues better than acting of Bei Wei Wei. And you can feel the chemistry between leads almost immediately.

Comparing the two in Memory Lost you get a way better OTP and a more exiting plot, with good twists, in Love O2O you get excellent side characters and realistic geek environment (Unlike some infamous shows).